Niobium is one of the most important and rarest metals, and is used in the electronic and energy industries. However, it’s extremely high melting point and oxygen affinity limits the manufacture of Nb coating materials. Here, a Nb coating material is manufactured using a kinetic spray process followed by hot isotactic pressing to improve its properties. OM (optical microscope), XRD (X-ray diffraction), SEM (scanning electron microscopy), and Vickers hardness and EPMA (electron probe micro analyzer) tests are employed to investigate the macroscopic properties of the manufactured Nb materials. The powder used to manufacture the material has angular-shaped particles with an average particle size of 23.8 μm. The porosity and hardness of the manufactured Nb material are 0.18% and 221 Hv, respectively. Additional HIP is applied to the manufactured Nb material for 4 h under an Ar atmosphere after which the porosity decreases to 0.08% and the hardness increases to 253 Hv. Phase analysis after the HIP shows the presence of only pure Nb. The study also discusses the possibility of using the manufactured Nb material as a sputtering target.

A bulk-type Ta material is fabricated using the kinetic spray process and its microstructure and physical properties are investigated. Ta powder with an angular size in the range 9-37 μm (purity 99.95%) is sprayed on a Cu plate to form a coating layer. As a result, ~7 mm-sized bulk-type high-density material capable of being used as a sputter material is fabricated. In order to assess the physical properties of the thick coating layer at different locations, the coating material is observed at three different locations (surface, center, and interface). Furthermore, a vacuum heat treatment is applied to the coating material to reduce the variation of physical properties at different locations of the coating material and improve the density. OM, Vickers hardness test, SEM, XRD, and EBSD are implemented for analyzing the microstructure and physical properties. The fabricated Ta coating material produces porosity of 0.11~0.12%, hardness of 311~327 Hv, and minor variations at different locations. In addition, a decrease in the porosity and hardness is observed at different locations upon heat treatment.

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• Sintering Behavior and Microstructures of Tantalum and Tantalum-Tungsten Alloys Powders
  Youngmoo Kim, Sung Ho Yang, Seong Lee, Sung Ho Lee, Joon-Woong Noh
  Journal of Korean Powder Metallurgy Institute.2020; 27(5): 373.     CrossRef
• Manufacturing of Large-Scale Cold-Sprayed Ta Target Material and Its Sputtering Property
  Gi-Su Ham, Dong-Yeol Wi, Jun-Mo Yang, Kee-Ahn Lee
  Journal of Thermal Spray Technology.2019; 28(8): 1974.     CrossRef
• Mechanical properties of Mo-Nb-Si-B quaternary alloy fabricated by powder metallurgical method
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  International Journal of Refractory Metals and Hard Materials.2017; 65: 14.     CrossRef

The effect of heat treatment environment on the microstructure and properties of tantalum coating layer manufactured by kinetic spraying was examined. Heat treatments are conducted for one hour at 800°C, 900°C, and 1000°C in two different environments of vacuum and Ar gas. Evaluation of microstructure and physical properties are conducted. High density α- tantalum single phase coating layer with a porosity of 0.04% and hardness of 550 Hv can be obtained. As heat treatment temperature increases, porosity identically decreases regardless of heat treatment environment (vacuum and Ar gas). Hardness of heat treated coating layer especially in Ar gas environment deceases from 550 Hv to 490 Hv with increasing heat treatment temperature. That in vacuum environment deceases from 550 Hv to 530 Hv. The boundary between particles became vague as heat treatment temperature increases. Oxygen distribution of tantalum coating layer is minute after heat treatment in vacuum environment than Ar gas environment.

Citations

Citations to this article as recorded by  

• Sintering Behavior and Microstructures of Tantalum and Tantalum-Tungsten Alloys Powders
  Youngmoo Kim, Sung Ho Yang, Seong Lee, Sung Ho Lee, Joon-Woong Noh
  Journal of Korean Powder Metallurgy Institute.2020; 27(5): 373.     CrossRef